Ridiculous bill

I've just received my first bill since changes were made to my account (phone line and fibre). Unsurprisingly it's completely wrong and ridiculously high, with double charging. Please sort this out ASAP.

Much to my surprise I was able to get through in online chat. This should have been resolved but it will take 3-5 working days for my bill to change (or will I get a separate refund?). The bill was overstated by £27.45.